Mapping six (6) eight (8) mbit/s signals to a SONET frame

ABSTRACT

A system ( 104 ) is provided for filling a SONET SPE ( 204, 300, 500, 600, 700 ) with bytes of digital information. The system is comprised of data input ports ( 1 - 6 ) configured to receive payload signals comprised of payload information. The system is also comprised of data processing circuits configured to transfer bytes of payload information in sequence from the payload signals. The data processing circuits are also configured to break the payload information into byte segments. The data processing circuits are further configured to map the byte segments to the SONET SPE in a byte by byte manner. The SONET SPE is comprised of cells. The cells are filled from top to bottom in a manner proceeding row by row, from left to right in each row. A method for filling the SONET SPE with bytes of digital information corresponding to payload signals is also provided.

BACKGROUND OF THE INVENTION

1. Statement of the Technical Field

The invention concerns the transportation of digital information onoptical media. More particularly, the invention concerns thetransportation of a plurality of eight (8) megabit per second signals inaccordance with a Synchronous Optical Network (SONET) standard.

2. Description of the Related Art

A Synchronous Optical Network (SONET) provides a system for transmittingdigital payload information (for example, voice, video or data traffic)over an optical fiber and/or a copper wire. The basic unit oftransmission for SONET is Synchronous Transport Signal one (STS-1). TheSTS-1 bit transfer rate equals 51.840 megabits per second. In thisregard, STS-1 provides a framing format used for the transmission ofcontrol and digital information within a SONET based network. A STS-1frame consists of ninety (90) columns by nine (9) rows of bytes. TheSTS-1 frame consists of a transport overhead (TOH) and a synchronouspayload envelope (SPE). The TOH occupies three (3) columns by nine (9)rows of bytes. The TOH includes section and line control information.The transport overhead bandwidth is approximately 2 megabits per second.The SPE occupies eighty-seven (87) columns by nine (9) rows of bytes.The SPE includes path overhead (POH) and digital payload information(for example, voice, video or data traffic). The SPE bandwidth isapproximately fifty (50) megabits per second.

Virtual tributaries (VTs) are subsets of STS-1. VTs transport digitalinformation at a lower bit rate than an STS-1 format. There are four (4)standard defined VT sizes suitable for a Time Division Multiplexing(TDM) Network hierarchy. These include a VT1.5 (i.e., bit transfer rateequals 1.728 megabits per second), a VT2 (i.e., bit transfer rate equals2.304 megabits per second), a VT3 (i.e., bit transfer rate equals 3.456megabits per second), and a VT6 (i.e., bit transfer rate equals 6.912megabits per second). It should be understood that two or more VTs canbe grouped together using a virtual concatenation technique to from asingle STS entity having a higher bit rate than its constituent VTs.

Various private and governmental clients have specific bit rates atwhich they prefer to transmit digital payload information (for example,voice, video or data traffic) through a network, such as a TDM Network.For example, a client prefers eight (8) megabits of digital informationto be transmitted through a TDM Network every second. In such ascenario, the eight (8) megabits per second signal needs to be mapped toa SONET frame. One technique that can be used for this purpose requiresmapping the eight (8) megabits per second signal into a fifty (50)megabits per second SPE. However, this technique suffers from certaindrawbacks. Specifically, this technique is inefficient because less thanone sixth (⅙) of the SPE bandwidth is used.

Another technique that can be used for this purpose requires the mappingof the eight (8) megabits per second signal to a single VT. However,there are no appropriately sized VTs that can accommodate an eight (8)megabits per second transfer rate directly.

Yet another technique that can be used for this purpose requiresemploying virtual concatenation. In this regard, virtual concatenationof four (4) VT2s can form an eight (8) megabits per second signals.However, this technique also suffers from drawbacks. Specifically, thistechnique requires special hardware, such as an inverse multiplexer, tobreak the eight (8) megabits per second into four (4) VT2s and toreassemble the eight (8) megabits per second signal.

In view of the forgoing, there remains a need for a method of mapping aneight (8) megabits per second signal into a SONET frame without wastingbandwidth.

SUMMARY OF THE INVENTION

The invention concerns a system for filling a SONET SPE with bytes ofdigital information. The system is comprised of one or more data inputports configured to receive eight (8) Mbit/s signals. The eight (8)Mbit/s signals include payload information. The system is also comprisedof one or more data processing circuits configured to transfer bytes ofpayload information in sequence from each of the eight (8) Mbit/ssignals. The data processing circuits are also configured to break thepayload information into one or more byte segments. Each of the bytesegments is comprised of one hundred twenty-eight (128) bytes of payloadinformation. The data processing circuits are further configured to mapthe bytes segments to the SONET SPE in a byte by byte manner. The SONETSPE is comprised of a plurality of cells in rows one through nine (1-9),columns one through eighty-seven (1-87). The cells are filled from topto bottom in a manner proceeding row by row, from left to right in eachrow. The data processing circuits are configured to insert bytes of pathoverhead data into cells in rows one through nine (1-9), column one (1)of the SONET SPE or at the SONET SPE starting location defined by one ormore SONET transport overhead (TOH) pointer bytes.

According to an embodiment of the invention, the data processingcircuits are configured to insert a byte of data into the SONET SPEimmediately before each respective one of the byte segments. The byte ofdata is selected from the group consisting of signaling information andcontrol information. According to another embodiment of the invention,the data processing circuits are configured to insert a byte of datainto the SONET SPE immediately after each respective one of the bytesegments. The byte of data is also selected from the group consisting ofsignaling information and control information.

According to another embodiment of the invention, the data processingcircuits are configured to insert bytes of signaling information orcontrol information after a first byte of path overhead data. Forexample, the data processing circuits can be configured to insert bytesof signaling information of control information into cells in row one(1), columns two through seven (2-7) of the SONET SPE. According to yetanother embodiment of the invention, the data processing circuits can beconfigured to insert bytes of signaling information or controlinformation into a last six (6) cells of the SONET SPE. For example, thedata processing circuits can be configured to insert bytes of signalinginformation or control information in row nine (9), columns eighty-twothrough eighty-seven (82-87) of the SONET SPE.

According to an aspect of the invention, the data processing circuitsare configured to determine whether each of the data input ports isactive or inactive. The data processing circuits are also configured toinsert at least one stuff byte into the SONET SPE if a data input portis inactive.

According to another aspect of the invention, the system is alsocomprised of one or more signaling input ports configured to receive aplurality of sixty-four (64) Kbit/s signals. As such, the dataprocessing circuits are configured to determine whether each of thesignaling input ports is active or inactive. The data processingcircuits are also configured to transfer bytes of signaling informationin sequence from a sixty-four (64) Kbit/s signal to obtain a signalingbyte segment into the SONET SPE if a corresponding signaling input portis active. The data processing circuits are configured to insert a byteof stuff information into the SONET SPE if a corresponding signalinginput port is inactive.

A method is also provided for filling a SONET SPE with a plurality ofbytes of digital information corresponding to a plurality of eight (8)Mbit/s signals. The eight (8) Mbit/s signals include payloadinformation. The method includes transferring bytes of payloadinformation in sequence from each of the eight (8) Mbit/s signals. Themethod also includes breaking the payload information into one or morebyte segments. Each of the byte segments are comprised of one hundredtwenty-eight (128) bytes of payload information. The method furtherincludes mapping the byte segments to the SONET SPE in a byte by bytemanner. The SONET SPE is comprised of a plurality of cells in rows onethrough nine (1-9), columns one through eight-seven (1-87). The cells infilled from top to bottom in a manner proceeding row by row, from leftto right in each row. The method includes inserting bytes of pathoverhead data into cells in rows one through nine (1-9), column one (1)of the SONET SPE or at the SONET SPE starting location defined by one ormore SONET transport overhead (TOH) pointer bytes.

According to an embodiment of the invention, the method includesinserting a byte of data into the SONET SPE immediately before eachrespective one of the byte segments. The bytes of data is selected fromthe group consisting of signaling information and control information.According to another embodiment of the invention the method includesinserting a byte of data into the SONET SPE immediately after eachrespective one of the byte segments. This byte of data is also selectedfrom the group consisting of signaling information and controlinformation.

According to another embodiment of the invention, the method includesinserting bytes of signaling information or control information after afirst byte of path overhead date. For example, the method can includeinserting bytes of signaling information or control information intocells in row one (1), column two through seven (2-7)of the SONET SPE.According to yet another embodiment of the invention, the methodincludes inserting bytes of signaling information or control informationinto a last six (6) cells of the SONET SPE. For example, the method caninclude inserting bytes of signaling information or control informationin row nine (9), columns eighty-two through eighty-seven (82-87) of theSONET SPE.

According to an aspect of the invention, the method includes determiningwhether each data input port of a plurality of data input ports isactive or inactive. The method also includes inserting one or more stuffbytes into the SONET SPE if a data input port is inactive.

According to anther aspect of the invention, the method includesdetermining whether a signaling input port of a plurality of signalinginput ports is active or inactive. The method also includes receiving asixty-four (64) Kbit/s signal on at least one of the signaling inputports. The method further includes transferring bytes of signalinginformation in sequence from each received sixty-four (64) Kbit/s signalto obtain a signaling byte segment.

According to yet another aspect of the invention, each of the signalinginput ports corresponds to one of the data input ports. As such, asixty-four (64) Kbit/s signal received at an active signaling input portcorresponds with an eight (8) Mbit/s signal received at a specificactive input port. In this regard, the method includes inserting asignaling byte segment into the SONET SPE if a signaling input portcorresponding to a specific data input port is active. The method alsoincludes inserting a byte of stuff information into the SONET SPE if asignaling input port corresponding to a specific data input port isinactive.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described with reference to the following drawingfigures, in which like numerals represent like items throughout thefigures, and in which:

FIG. 1 is a block diagram of a communications network with a SONETmapping system that is useful for understanding the invention.

FIG. 2 is a format diagram of a SONET STS-1 frame that is useful forunderstanding the invention.

FIG. 3 is a format diagram of a SONET synchronous payload envelope thatis useful for understanding the invention.

FIG. 4 is a flow diagram of a method for filling a SONET synchronouspayload envelope in accordance with the format shown in FIG. 3.

FIG. 5 is a format diagram of a SONET synchronous payload envelope thatis useful for understanding the invention.

FIG. 6 is a format diagram of a SONET synchronous payload envelope thatis useful for understanding the invention.

FIG. 7 is a format diagram of a SONET synchronous payload envelope thatis useful for understanding the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described more fully hereinafter withreference to accompanying drawings, in which illustrative embodiments ofthe invention are shown. This invention, may however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. For example, the present invention can beembodied as a method, a data processing system, or a computer programproduct. Accordingly, the present invention can take the form as anentirely hardware embodiment, an entirely software embodiment, or ahardware/software embodiment.

The present invention can be realized in one computer system. Any kindof computer system or other apparatus adapted for carrying out themethods described herein is suited. A typical combination of hardwareand software can be a general-purpose computer system. Thegeneral-purpose computer system can have a computer program that cancontrol the computer system such that it carries out the methodsdescribed herein.

The present invention can take the form of a computer program product ona computer-usable storage medium (for example, a hard disk or a CD-ROM).The computer-usable storage medium can have computer-usable program codeembodied in the medium. The term computer program product, as usedherein, refers to a device comprised of all the features enabling theimplementation of the methods described herein. Computer program,software application, computer software routine, and/or other variantsof these terms, in the present context, mean any expression, in anylanguage, code, or notation, of a set of instructions intended to causea system having an information processing capability to perform aparticular function either directly of after either or both of thefollowing: a) conversion to another language, code, or notation; or b)reproduction in a different material form.

Embodiments of the present invention will now be described with respectto FIG. 1 through FIG. 7. Some embodiments of the present inventionprovide methods, systems, and apparatus relating to filling a SONET STSframe with bytes of path overhead data, bytes of digital payloadinformation for a plurality of eight (8) Mbit/s signals, and bytes ofsignaling, control, and/or stuff information. Accordingly, embodimentsincluding the listed functions are discussed further below.

As used herein, the term stuff information refers to one or more bytesthat contain neither payload data nor signaling information. Stuffinformation is comprised of data bytes used as an aid to assembling dataframes as described herein. This stuffing information or stuffing bitsare used as dummy data and will generally be lacking in actualinformation content.

Referring now to FIG. 1, there provided a block diagram of acommunications network 100 that is useful for understanding theinvention. Communications network 100 is comprised of a source node 102,a mapping system 104, and a SONET transmitter 106. The communicationsnetwork 100 is also comprised of a SONET receiver 110 and a destinationnode 112. The communications network 100 is further comprised of a SONETbased network 108.

The source node 102 includes hardware and software for generating one ormore signals including digital information such as voice, video, and/ordata traffic. Such digital information can be thought of as the payloadinformation of data of the source node as it generally comprises theinformation that is of primary interest to the user. The source node 102optionally also generates a second type of information which will bereferred to herein as signaling or control information. The source node102 also includes hardware and software for transmitting the generatedsignals to the mapping system 104. As shown in FIG. 1, the source node102 can transmit signals at various data transfer rates. For example,the source node 102 can operate at an eight (8) megabits per second(Mbit/s) transfer rate for digital payload information (such as voice,video, and/or data traffic). The source node 102 can also operate at asixty-four (64) kilobits per second (Kbit/s) transfer rate for signalinginformation. Still, the invention is not limited in this regard. Thesource node 102 can operate at a transfer rate that is less than orequal to sixty-four (64) kilobits per second (Kbit/s) for signaling andcontrol information.

Referring again to FIG. 1, the mapping system 104 is comprised of an 8Mb to STS-1 mapping and framing device (8 Mb-STS MFD) 114, an 8 Mb toSTS-1 demapping and deframing device (8 Mb-STS DDD) 118, controllers120-1, 120-2, and memories 116-1, 116-2. The 8 Mb-STS MFD 114 includeshardware and software for receiving one or more signals having a definedbit transfer rate (for example, an eight (8) Mbit/s transfer rate and asixty-four (64) Kbit/s transfer rate). According to an embodiment of theinvention, the 8 Mb-STS MFD 114 can be comprised of six (6) eight (8)Mbit/s data input ports 1, 2, 3, 4, 5, 6 to provide a transmission pathfor digital payload information, such as voice and data. The 8 Mb-STSMFD 114 can also be comprised of six (6) sixty-four (64) Kbit/ssignaling channel ports 7, 8, 9, 10, 11, 12 to provide a transmissionpath for signaling information (such as setup and packet data). the 8Mb-STS MFD 114 can further be comprised of a control input port 13 toprovide a transmission path for control information and/or managementinformation. Still, it should be appreciated that the invention is notlimited in this regard. The 8 Mb-STS MFD 114 can be comprised of variousnumbers of data input ports, signaling channel ports, andcontrol/management input ports in accordance with a communicationsnetwork 100 application.

According to an aspect of the invention, the 8 Mb-STS MFD 114 can relatea signal including payload information arriving on a particular datainput port 1, 2, 3, 4, 5, 6 to a signal including signaling informationarriving on a particular signaling channel port 7, 8, 9, 10, 11, 12. Assuch, each signaling channel port 7, 8, 9, 10, 11, 12 can correspond toa particular data input port 1, 2, 3, 4, 5, 6.

According to a preferred embodiment of the invention, a fixedcorrespondence method is employed for relating a signal includingpayload information arriving on a particular data input port 1, 2, 3, 4,5, 6 to a signal including signaling information arriving on aparticular signaling channel port 7, 8, 9, 10, 11, 12. In such ascenario, signaling channel port 7 corresponds to data input port 1.Similarly, signaling channel port 8 corresponds to data input port 2.Likewise, signaling channel port 9 corresponds to data input port 3.Signaling channel ports 10, 11, 12 correspond to data input ports 4, 5,6, respectively.

According to another embodiment of the invention, a flexible,configurable mapping method is employed for relating a signal includingpayload information arriving on a particular data input port 1, 2, 3, 4,5, 6 to a signal including signaling information arriving on aparticular signaling channel port 7, 8, 9, 10, 11, 12. In such ascenario, signaling channel port 7 can be selected to correspond to anydata input port 1, 2, 3, 4, 5, 6. Similarly, signaling channel port 8can be selected to correspond to any data input port 1, 2, 3, 4, 5, 6that has not already been assigned to signaling channel port 7.Likewise, signaling channel port 9 can be selected to correspond to anydata input port 1, 2, 3, 4, 5, 6 that has not already been assigned tosignaling channel ports 7 and 8. Signaling channel ports 10, 11, and 12can be selected to correspond to any data input port 1, 2, 3, 4, 5, 6 inthe same manner. As will be understood by a person skilled in the art, aone (1) input, six (6) output selector device is required for each ofthe six (6) signaling channel ports for implementing such a flexible,configurable mapping method it should be understood that the one (1)input, six (6) output selector device is capable of no selection when asignaling channel port is not present.

The 8 Mb-STS MFD 114 can also be comprised of one or more dataprocessing circuits configured to transfer bytes of payload informationin sequence from a received eight (8) Mbit/s signal and break thepayload information into a plurality of byte segments (for example, eachbyte segment can include one hundred twenty-eight (128) bytes of payloadinformation). Similarly, the one or more data processing circuitscomprising 8 Mb-STS MFD 114 can be configured to transfer bytes ofsignaling information in sequence from a received sixty-four (64) Kbit/ssignal and perform processing on the signaling information to obtain asignaling byte segment. For example, the signaling byte segment can becomprised of one (1) byte. Likewise, the 8 Mb-STS MFD 114 can transferbytes of control information in sequence from a receivedcontrol/management signal and perform processing on the controlinformation to obtain a one (1) byte segment.

As shown in FIG. 1, the 8 Mb-STS MFD 114 is coupled to the memory 116-1which may be a RAM, a disk drive, and/or any other form of programbulk-storage. As such, the 8 Mb-STS MFD 114 can store digital,signaling, and/or control information in the memory 116-1 according to adesired population scheme. For example, a plurality of bytes of payloadinformation can be stored in a table format such that the plurality ofbytes of payload information are associated with a particular data inputport 1, 2, 3, 4, 5, 6. Similarly, a plurality of bytes of signalinginformation can be stored in a table format such that the plurality ofbytes of signaling information can be associated with a particularsignaling channel port 7, 8, 9, 10, 11, 12. The 8 Mb-STS MFD 114 canalso retrieve the digital, signaling, and/or control information fromthe memory 116-1.

The 8 Mb-STS MFD 114 also includes up-counters 122, 124, 126, 128, 130configured to perform counter-increment functions. The up-counters canbe implemented in any suitable manner. For example, the up-counters canbe implemented in software within one or more data processing circuitsincluded in 8 Mb-STS MFD 114. Alternatively, the up-counters can beimplemented as separate hardware entities. The up-counter 122 can beselected as a SONET synchronous payload envelop (SPE) row counter. Theup-counter 124 can be selected as a SONET SPE column counter. Theup-counter 126 can be selected as an eight (8) Mbit/s signal counter 130can be selected as a payload information byte counter. The counters 122,124, 126, 128, 130 are well know to persons skilled in the art. Thus,counters will not be described in great detail herein.

The 8 Mb-STS MFD 114 further includes hardware and software forexecuting a method to map a plurality of bytes of payload information(for example, one hundred twenty-eight bytes of payload information)into a SPE of a SONET STS-1 frame (described below in relation to FIG.2). This method includes consecutively inserting the plurality of bytesof payload information into the SPE of a SONET STS-1 frame. A number ofhardware/software routines implementing this method are described indetail below (in relation to FIG. 3 through FIG. 7). However, it shouldbe appreciated that the invention is not limited in this regard. Thismethod may be implemented in any form such as an entirely hardwareembodiment, an entirely software embodiment, or a hardware/softwareembodiment.

In addition to the one or more data processing circuits included in 8Mb-STS MFD 114, the 8 Mb-STS MFD 114 can include hardware and/orsoftware for inserting bytes of signaling, control, and/or stuffinformation into the SPE of a SONET STS-1 frame (described below inrelation to FIG. 2). A number of hardware/software routines implementingthis inserting function are also described below (in relation to FIG. 3through FIG. 7). However, it should be appreciated that the invention isnot limited in this regard. This method of inserting bytes of signaling,control, and/or stuff information into the SPE may be implemented in anyform such as an entirely hardware embodiment, an entirely softwareembodiment, or a hardware/software embodiment.

This 8 Mb-STS MFD 114 also includes hardware and software for insertingbytes of a section overhead data, a line overhead data, and a pathoverhead data into a SONET STS-1 frame (described below in relation toFIG. 2). A person skilled in the art will appreciate that a STS-1 is thebasic unit of transmission for the SONET based network 108. In thisregard, a STS-N (for example, STS-1, STS-3, STS-12, STS-48, and/orSTS-192) formatted signal can be obtained by interleaving ‘N’ STS-1formatted signals. The techniques used for interleaving a plurality ofSTS-1 formatted signals are well known to persons skilled in the art.Thus, such techniques will not be described in great detail herein.However, it should be appreciated that any such technique can be usedwithout limitation.

A person skilled in the art will appreciate that functions necessary forinserting various types of overhead data as described above, can beperformed by a device external to the 8 Mb-STS MFD 114 (such as, anexternal SONET framer). In this regard, the architecture of FIG. 1 canbe amended accordingly. For example, the device 114 can be selected asan 8 Mb-STS mapping device, exclusive of SONET framing functions. The 8Mb-STS mapping device can be absent of hardware and/or softwareconfigured to perform the overhead inserting functions. The 8 Mb-STSmapping device can be followed by a SONET framer. SONET framers are wellknow to persons skilled in the art. Thus, SONET framers will not bedescribed in great detail herein.

The controller 120-1 is coupled to the 8 Mb-STS MFD 114 via a bus 142.The controller 120-1 is comprised of a circuit configured forcommunicating signals to the 8 Mb-STS MFD 114. The signals can includecontrol information and/or management information. As will be understoodby those skilled in the art, the controller 120-1 can be externallyconnected to a local or a remote network management system (not shown)so as to provide a control capability for an operator to configure the 8Mb-STS MFD 114. In this regard, it should be appreciated that such aconfiguration can provide a control capability for an operator toconfigure the data input ports 1, 2, 3, 4, 5, 6 and the signalingchannel ports 7, 8, 9, 10, 11, 12 of the 8 Mb-STS MFD 114.

The SONET transmitter 106 includes hardware and software fortransmitting a SONET STS-1 signal over the SONET based network 108. TheSONET based network 108 is well known to persons skilled in the art.Thus, the SONET based network will not be described in great detailherein.

The SONET receiver 110 includes hardware and software for receiving aSONET STS-1 formatted signal. The SONET receiver 110 also includes acircuit configured for transmitting the received signal to the 8 Mb-STSDDD 118.

The 8 Mb-STS DDD 118 includes hardware and software for de-framing aSONET STS-1 formatted signal. The term de-framing as used herein refersto the process of extracting bytes of section overhead data, lineoverhead data, and path overhead data from the SONET signal. It shouldbe appreciated that there are many methods know in the art forde-framing a SONET STS-1 formatted signal. A person skilled in the artwill appreciate that any such method can be used without limitation.

A person skilled in the art will appreciate that overhead extractingfunctions, described above, can be performed by a device external to the8 Mb-STS DDD 118 (such as, an external SONET deframer). In this regard,the architecture of FIG. 1 can be amended accordingly. For example, thedevice 118 can be selected as an 8 Mb-STS demapping device exclusive ofSONET de-framing functions. The 8 Mb-STS demapping device can be absentof hardware and/or software configured to perform the overheadextracting functions. The 8 Mb-STS demapping device can be followed by aSONET deframer. SONET deframers are well know to persons skilled in thepart. Thus, SONET deframers will not be described in great detailherein.

A shown in FIG. 1, the 8 Mb-STS DDD 118 also includes up-counters 132,134, 136, 138, 140 configured to perform counter-increment functions.The up-counters can be implemented in any suitable manner. For example,the up-counters can be implemented in software within one or more dataprocessing circuits included in 8 Mb-STS DDD 118. Alternatively, theup-counters can be implemented as separate hardware entities. Theup-counter 132 can be selected as a SONET SPE row counter. Theup-counter 134 can be selected as a SONET SPE column counter. Theup-counter 136 can be selected as an eight (8) Mbit/s signal counter.The up counter 138 can be selected as a signaling channel counter. Theup counter 140 can be selected as a payload information byte counter.The counters 132, 134, 136, 138, 140 are well known to persons skilledin the art. Thus, counters will not be described in great detail herein.

The 8 Mb-STS DDD 118 is also coupled to the memory 116-2, which may be aRAM, a disk drive, and/or any other form of program bulk-storage. Assuch, the 8 Mb-STS DDD 118 can store digital, signaling, and/or controlinformation in the memory 116-2 according to a desired population scheme(for example, a table format). The 8 Mb-STS DDD 118 can also retrievethe same from the memory 116-2.

The 8 Mb-STS DDD 118 includes hardware and software for performing theinverse functions of those executed by the 8 Mb-STS MFD 114. In thisregard, the destination node 112 can operate at the same rate service asthe source node 102 (for example, a rate service of eight (8) Mbit/s forpayload information and a rate service of sixty-four (64) Kbit/s forsignaling information). However, it should be appreciated that theinvention is not limited in this regard. For example, the 8 Mb-STS DDD118 can include hardware and software for performing SONET demappingfunction in accordance with a particular destination node 112 service(such as, a T1 rate service of 1.544 Mbit/s or a E1 rate service of2.048 Mbit/s).

A person skilled in the art will appreciate that communications network100 architecture is one embodiment of a communications network. However,the invention is not limited in this regard and any other communicationsnetwork architecture can be used without limitation. For example, theup-counters 132, 134, 136, 138, 140 can alternatively be selected asdown-counter circuits.

Referring now to FIG. 2, there is provided a format diagram of a SONETSTS-1 frame 200 that is useful for understanding the invention. TheSTS-1 frame 200 is comprised of ninety (90) columns by nine (9) rows ofbytes. Such a configuration provides eight hundred ten (90×9=810) bytesof information per frame.

The STS-1 frame 200 is further comprised of a transport overhead (TOH)202 and a synchronous payload envelope (SPE) 204. The TOH 202 occupiesthree (3) columns by nine (9) rows of bytes. In this regard, the TOH 202includes twenty-seven (3 columns×9 rows=27) bytes of information.Specifically, the TOH 202 includes data associated with section and linecontrol information (for example, A1, A2, J0, B2, and K1). The sectionand line control information is well known to persons skilled in theart. Thus, section and line control information will not be described ingreat detail herein.

The SPE 204 occupies eighty-seven (87) columns by nine (9) rows ofbytes. In this regard, the SPE 204 includes seven hundred eighty-three(87 columns×9 rows=783) bytes of information. The SPE 204 includes apath overhead (POH) 206 and a payload 208. As shown in FIG. 2, the POH206 occupies the first column of the SPE 204, thus includes nine (1column×9 rows=9) bytes of information. However, a person skilled in theart will understand that a pointer-adjusted SPE may have a POH startingbyte at a location other than row one (1), column one (1). This locationis typically defined by one or more SONET TOH pointer bytes. As such, itshould be appreciated that the STS-1 frame 200 architecture shown inFIG. 2 is provided merely for simplicity. The POH is will known topersons skilled in the art. Thus, the POH will not be described in greatdetail herein.

As shown in FIG. 2, the payload 208 occupies eighty-six (86) columns bynine (9) rows of bytes. In this regard, the payload 208 has a capacityof seven hundred seventy-four (86 columns×9 rows=774) bytes ofinformation (for example, payload information, signaling information,control information, and/or stuff information).

The foregoing description is useful for understanding a STS-1 frame 200.In this regard, a more detailed description of the STS-1 frame 200 canbe found in “Synchronous Optical Network (SONET)—Basic Descriptionincluding Multiplex Structures, Rates, and Formats,” provided by theAmerican National Standards Institute. The entire disclosure of thispublication is incorporated herein by reference.

Methods for Mapping a Plurality of Eight (8) Mbit/s Signals to a SONETSPE

Embodiments of the present invention will now be described with respectto FIG. 3 through FIG. 7. Some embodiments of the present inventionprovide methods, systems, and apparatus relating to filling a SONET STSframe with bytes of path overhead data, bytes of payload information fora plurality of eight (8) Mbit/s signals, and bytes of signaling,control, and/or stuff information. Accordingly, embodiments includingthe listed functions are discussed in detail below.

Referring now to FIG. 3, there is provided a format diagram of a SONETSPE 300 that is useful for understanding the invention. As shown in FIG.3, the SONET SPE 300 is comprised of a path overhead region 306 and apayload region 308. The path overhead region 306 occupies the firstcolumn of the SONET SPE 300, thus includes nine bytes 310, 312, 314,316, 318, 320, 322, 324, 326 of path overhead data. The payload region308 occupies eight-six (86) columns by nine (9) rows of bytes. As shownin FIG. 3, the payload region 308 is also comprised of six (6) bytes ofsignaling, control, and/or stuff information 330, 332, 334, 336, 338,340. The payload region 308 also includes seven hundred sixty-eight (86columns×9 rows−6 bytes=768) bytes of payload information 350, 352, 354,356, 358, 360 associated with six (6) eight (8) Mbit/s signals. In thisregard, the payload region 308 includes one hundred twenty-eight (768bytes/6 signals=128)bytes of payload information 350, 352, 354, 356,358, 360 per eight (8) Mbit/s signal.

It should be appreciated that a byte of signaling, control, and/or stuffinformation 330, 332, 334, 336, 338, 340 reside prior to the bytes ofpayload information 350, 352, 354, 356, 358, 360 associated with eacheight (8) Mbit/s signal. For example, byte 330 resides prior to thebytes of payload information 350 associated with a first eight (8)Mbit/s signal. Similarly, byte 332 resides prior to the bytes of payloadinformation 352 associated with a second eight (8) Mbit/s signal.Likewise, byte 334 resides prior to the bytes of payload information 354associated with a third eight (8) Mbit/s signals. Byte 336 resides priorto the bytes of payload information 356 associated with a forth eight(8) Mbit/s signal. Byte 338 resides prior to the bytes of payloadinformation 358 associated with a fifth eight (8) Mbit/s signal. Byte340 resides prior to the bytes of payload information 360 associatedwith a sixth eight (8) Mbit/s signal.

It should be further appreciated that the format of a SONET SPE 300provides for a method to transport a plurality of eight (8) Mbit/ssignals efficiently over the SONET based network 108. The transportefficiency can be described by mathematical Equation (1).Transport Efficiency (%)=(Total SPE bytes used/Payload Capacity)×100  (1)

First, consider the scenario where the six (6) bytes of signaling,control, and/or stuff information 330, 332, 334, 336, 340 are unused. Inthis case, the ‘Total SPE bytes used’ equals seven hundred sixty-eight(768). The ‘payload capacity’ equals seven hundred seventy-four (774).Therefore, the ‘transport efficiency’ equals approximately ninety-ninepoint two percent (99.2%). Alternatively, consider the scenario wherethe six (6) bytes of signaling, control, and/or stuff information 330,332, 334, 336, 338, 340 are used. As such, the ‘Total SPE bytes used’equals seven hundred seventy-four (774). The ‘payload capacity’ equalsseven hundred seventy-four (774). Thus, the ‘transport efficiency’equals one hundred percent (100%).

A person skilled in the art will appreciate that the format of a SONETSPE 300 is one embodiment of a SONET SPE format. However, the inventionis not limited in this regard and any other SONET SPE format can be usedwithout limitation.

Referring now to FIGS. 4A-4C, there is provided a flow diagram of amethod for filling a SONET SPE 300 in accordance with the format shownin FIG. 3. It should be appreciated that the SONET SPE 300 is filled ina manner that is in accordance with standards provided by the AmericanNational Standards Institute. For example, seven hundred eighty-three(783) cells in rows 1-9, columns 1-87 of the SONET SPE 300 are filledfrom top to bottom in a manner that proceeds row by row, from left toright in each row. see ANTSI T1.105, section 7.1 page 12.

Referring now to FIG. 4A, there is provided a method 400 for filling aSONET SPE 300. The method 400 begins at step 402 and continues to step404. In step 404, a determination is made as to which data input ports1, 2, 3, 4, 5, 6 of an 8 Mb-STS MFD 114 are active. Subsequently,control passes to step 406 where a determination is made as to whichsignaling channel port 7, 8, 9, 10, 11, 12 of the 8 Mb-STS MFD 114 areactive. In step 408, a determination is made as to whether of not acontrol input port 13 of the 8 Mb-STS MFD 114 is active. Aftercompleting step 408, the method 400 continues with step 410. In step410, the 8 Mb-STS MFD 114 receives eight (8) Mbit/s signals from asource 102. It should be appreciated that the 8 Mb-STS MFD 114 will onlyreceive eight (8) Mbit/s signals through the active data input ports 1,2, 3, 4, 5, 6. Similarly in step 412, the 8 Mb-STS MFD 114 receivessixty-four (64) Kbit/s signals from the source 102. It should beappreciated that the 8 Mb-STS MFD 114 will only receive sixty-four (64)Bit/s signals through the active signaling channel ports 7, 8, 9, 10,11, 12. In step 414, the 8 Mb-STS MFD 114 receives control signals froma controller 120-1 if the control input port 13 is active. Afterreceiving eight (8) Mbit/s signals, sixty-four (64) Kbit/s signals,and/or control signals, the method 400 continues with step 416.

In step 416, the received signals are processed. This can involvetransferring bytes of payload information in sequence from the receivedeight (8) Mbit/s signals. The payload information can be broken into aplurality of byte segments (for example, one hundred twenty-eight (128)byte segments per eight (8) Mbit/s signal). This step can also involvetransferring bytes of signaling information in sequence from a receivedsixty-four (64) Kbit/s signal. Processing can be performed on thesignaling information to obtain a one (1) byte segment. This step canfurther involve parsing control information from a receivedcontrol/management signal. Processing can be performed on the controlinformation to obtain a one (1) byte segment. The bytes of digital,signaling, and/or control information are stored in a memory 116-1.

After step 416, control passes to step 418 where a byte of path overheaddata 310 is inserted into a cell at row one, column one of a SONET SPE300. This step can involve performing functions to set each of a SONETSPE row counter 122 and a SONET SPE column counter 124 to a value of one(1). Subsequently, step 420 is performed where a byte of signaling,control, or stuff information 330 is inserted into a cell in row one,column two of the SONET SPE 300. It should be appreciated that stuffinformation is inserted into the cell in row one, column two of theSONET SPE 300 when signaling channel port 7 is inactive. It should alsobe appreciated that this step can involve performing functions toincrement a SONET SPE column counter 124 by one (+1) and to set asignaling channel counter 128 to one (1). This step can also involvequerying the memory 116-1 for the byte of signaling, control, and/orstuff information 330 and receiving the same from the memory 116-1.

After inserting a byte of signaling, control, and/or stuff informationinto the payload region 308, step 422 is performed. In step 422,eighty-five (85) bytes of payload information associated with a firsteight (8) Mbit/s signal are mapped to the SONET SPE 300 in a byte bybyte manner. It should be appreciated that the eighty-five (85) cellsare filled in a row by row, from left to right manner. Therefore, step422 involves consecutively inserting eighty-five (85) bytes of payloadinformation to the last eighty-five (85) cells in row one of the SONETSPE 300. It should be appreciated that this step can involve insertingbytes of stuff information to the cells in row one of the SONET SPE 300when the data input port 1 is inactive. It should also be appreciatedthat this step can involve performing functions to increment a SONET SPEcolumn counter 124 each time a byte is inserted into a cell. This stepcan further involve performing functions to set an eight (8) Mbit/ssignal counter 126 to a value of one (1), to set a payload informationbyte counter 130 to a value of one (1), and to increment the payloadinformation byte counter 130 by one (+1) each time a byte of payloadinformation is inserted into a cell. It should further be appreciatedthat this step can involve querying the memory 116-1 for the eighty-five(85) bytes of payload information and receiving the same from the memory116-1.

Upon completing step 422, control passes to step 424 where method 400continues to a row two of the SONET SPE 300. This step can involveperforming a function to increment the SONET SPE row counter 122 by one(+1). In step 426, a byte of path overhead data 312 is inserted into acell at row two, column one of a SONET SPE 300. This step can involveperforming a function to re-set the SONET SPE column counter 124 to one(1).

Thereafter, step 428 is performed where forty-three (43) bytes ofpayload information associated with the first eight (8) Mbit/s signalare mapped to the SONET SPE 300 in a byte by byte manner. Theforty-three (43) cells in row two of the SONET SPE 300 are filled in arow by row, from left to right manner. Therefore, step 422 involvesconsecutively inserting forty-three (43) bytes of payload information toforty-three (43) cells in row two of the SONET SPE 300. It should beappreciated that this step can involve inserting bytes of stuffinformation to the cells in row two of the SONET SPE 300 when the datainput port 1 is inactive. It should also be appreciated that that thisstep can involve performing functions to increment a SONET SPE columncounter 124 by one (+1) each time a byte is inserted into a cell. Thisstep can involve performing functions to increment the payloadinformation byte counter 130 by one (+1) each time a byte of payloadinformation is inserted into a cell. It should further be appreciatedthat this step can involve querying the memory 116-1 for the forty-three(43) bytes of payload information and receiving the same from the memory116-1.

After step 428, control passes to a step 430. In step 430, a byte ofsignaling, control, or stuff information 332 is inserted into thepayload region 308. This step involves inserting the byte of signaling,control, or stuff information 332 into a cell in row two, columnforty-five of the SONET SPE 300. It should be appreciated that a byte ofstuff information is inserted into the cell in row two, columnforty-five of the SONET SPE 300 when signaling channel port 2 isinactive. It should also be appreciated that this step can involveperforming functions to increment the SONET SPE column counter 124 byone (+1). This step can involve performing functions to increment thesignaling channel counter 128 by one (+1). It should further beappreciated that this step can involve querying the memory 116-1 for thebyte of signaling, control, or stuff information 332 and receiving thesame from the memory 116-1.

Subsequent to inserting the byte 332 into the payload region 308, step432 is performed. In step 432, forty-two (42) bytes of payloadinformation associated with a second eight (8) Mbit/s signal are mappedto the SONET SPE 300 in a byte to byte manner. It should be appreciatedthat cells of the payload region 308 are filled in a row by row, fromleft to right manner. Therefore, step 432 involves consecutivelyinserting forty-two (42) bytes of payload information into the remainingforty-two (42) cells in row two of the SONET SPE 300. It should beappreciated that this step can involve inserting bytes of stuffinformation to the forty-two (42) cells in row two of the SONET SPE 300when data input port 2 is inactive. This step can also involveperforming functions to increment the 8 Mbit/s signal counter 126 by one(+1), re-set the payload information byte counter 130 to a value one(1), and increment the payload information byte counter 130 by one (+1)search time a byte of payload information is inserted into a cell. Thisstep further involves performing functions to increment the SONET SPEcolumn counter 124 by one (+1) each time a byte is inserted into a cell.After mapping the forty-two (42) bytes to the SONET SPE 300, controlpasses to step 438 in FIG. 4B.

In step 438, the method 400 continues to a row three of the SONET SPE300. This step can involve performing a function to increment the SONETSPE row counter 122 by one (+1). After step 438, control passes to step440 where a byte of path overhead data 314 is inserted into a cell atrow three, column one of a SONET SPE 300. This step can involveperforming a function to re-set the SONET SPE column counter 124 to one(1).

In step 442, eight-six (86) bytes of payload information associated witha second eight (8) Mbit/s signal are mapped to the SONET SPE 300 in abyte to byte manner. It should be appreciated that cells of the payloadregion 308 are filled in a row by row, from left to right manner.Therefore, step 442 involves consecutively inserting the eighty-six (86)bytes of payload information into eight-six (86) cells in row three ofthe SONET SPE 300. It should be appreciated that this step can involveinserting bytes of stuff information to the eighty-six (86) cells in rowthree of the SONET SPE 300 when data input port 2 is inactive. This stepcan also involve performing a function to increment the SONET SPE columncounter 124 and the payload information byte counter 130 by one (+1)each time a byte of payload information is inserted into a cell. Thisstep can further involve querying a memory 116-1 for the eighty-six (86)bytes of payload information and receiving the same from the memory116-1.

After the eighty-six (86) bytes of the second eight (8) Mbit/s signalare mapped to the SONET SPE 300, control passes to step 444. In step444, the method 400 continues to a row four of the SONET SPE 300. Thisstep can involve performing a function for incrementing the SONET SPErow counter 122 by one (+1). Subsequently, step 446 is performed where abyte of path overhead data 316 is inserted into a cell at row four,column one of a SONET SPE 300. This step can involve performing afunction to re-set the SONET SPE column counter 124 to one (1).

In step 448, a byte of signaling, control, or stuff information 334 isinserted into the SONET SPE 300. This step involves inserting the byteof signaling, control, or stuff information 334 into a cell in row four,column two of the SONET SPE 300. It should be appreciated that a byte ofstuff information is inserted into the cell in row four, column two theSONET SPE 300 when signaling channel port 3 is inactive. It should bealso appreciated that this step can involve performing a function toincrement the SONET SPE column counter 124 by one (+1). This step canalso involve incrementing the signaling channel counter 128 by one (+1).It should further be appreciated that this step can involve querying thememory 116-1 for the byte of signaling, control, or stuff information334 and receiving the same from the memory 116-1.

Subsequently, the method 400 continues with step 450 where eighty-five(85) bytes of payload information associated with a third eight (8)Mbit/s signal are mapped to the SONET SPE 300 in a byte to byte manner.It should be appreciated that the cells of the payload region 308 arefilled in a row by row, from left to right manner. In this regard, step450 involves consecutively inserting the eighty-five (85) bytes ofpayload information into the remaining cells in row four of the SONETSPE 300. It should be understood that this step can involve insertingbytes of stuff information to the eighty-five (85) cells in row four ofthe SONET SPE 300 when the data input port 3 is inactive. This step canalso involve performing a function to increment the eight (8) Mbit/ssignal counter 126 by one (+1). This step can further involve performingfunctions to increment the SONET SPE column counter 124 and the payloadinformation byte counter 130 by one (+1) each time a byte of payloadinformation is inserted into a cell. It should also be understood thatthis step can involve querying the memory 116-1 for the eighty-five (85)bytes of payload information and receiving the same from the memory116-1.

Thereafter, control passes to step 452 where the method 400 continues toa row five of the SONET SPE 300. This step can involve performing afunction to increment the SONET SPE row counter 122 by one (+1). In step454, a byte of path overhead data 318 is inserted into a cell at rowfive, column one of a SONET SPE 300. This step can involve performing afunction to re-set the SONET SPE column counter 124 to one (1).

After inserting byte 318 into the SONET SPE 300, step 456 is performed.In step 456, forty-three (43) bytes of payload information of the thirdeight (8) Mbit/s signal are mapped to the SONET SPE 300 in a byte tobyte manner. It should be appreciated that the cells of the payloadregion 308 are filled in a row by row, from left to right manner. Inthis regard, step 450 involves consecutively inserting the forty-three(43) bytes of payload information into forty-three (43) cells in rowfive of the SONET SPE 300. It should be appreciated that this step caninvolve inserting bytes of stuff information to the cells in row five ofthe SONET SPE 300 when the data input port 3 is inactive. This step canalso involve performing a function to increment the SONET SPE columncounter 124 and the payload information byte counter 130 by one (+1)each time a byte of payload information is inserted into a cell. Thisstep can further involve querying the memory 116-1 for the forty-three(43) bytes of payload information and receiving the same from the memory116-1.

As shown in FIG. 4B, the method 400 continues with step 458 where a byteof signaling, control, or stuff information 336 is inserted into theSONET SPE 300. This step involves inserting the byte of signaling,control, or stuff information 336 into a cell in row five, columnforty-five of the SONET SPE 300. It should be appreciated that a byte ofstuff information is inserted into the cell in row five, columnforty-five of the SONET SPE 300 when signaling channel port 10 isinactive. It should also be appreciated that this step can involveperforming a function to increment the signaling channel counter 128 andthe SONET SPE column counter 124 by one (+1). It should further beappreciated that this step can involve querying the memory 116-1 for thebyte of signaling, control, or stuff information 336 and receiving thesame from the memory 116-1.

In step 460, forty-two (42) bytes of payload information associated witha fourth eight (8) Mbit/s signal are mapped to the SONET SPE 300 in abyte by byte manner. It should be appreciated that the cells of thepayload region 308 are filled in a row by row, form left to rightmanner. In this regard, step 434 involves consecutively inserting theforty-two (42) bytes of payload information into the remaining cells inrow five of the SONET SPE 300. It should be understood that this stepcan involve inserting bytes of stuff information to the cells in rowfive of the SONET SPE 300 when data input port 4 is inactive. It shouldalso be understood that this step can involve performing a function toincrement the eight (8) Mbit/s signal counter 126 by one (+1). This stepcan also involve performing a function to increment the SONET SPE columncounter 124 and the payload information byte counter 130 by one (+1)each time a byte of payload information is inserted into a cell. Thisstep can further involve querying the memory 116-1 for the forty-two(42) bytes of payload information and receiving the same from the memory116-1.

In step 462, the method 400 continues to a row six of the SONET SPE 300.This step can involve performing a function to increment the SONET SPErow counter 122 by one (+1). Thereafter, control passes to step 464where a byte of path overhead data 320 is inserted into a cell at rowsix, column one of a SONET SPE 300. This step can involve performing afunction to re-set the SONET SPE column counter 124 to one (1). Afterinserting byte 320 into the SONET SPE 300, step 466 is performed.Thereafter, control passes to step 470 in FIG. 4C.

In step 470, eight-six (86) bytes of payload information associated witha fourth eight (8) Mbit/s signal are mapped to the SONET SPE 300 in abyte by byte manner. It should be appreciated that the cells of theSONET SPE 300 are filled in a row by row, from left to right manner. Inthis regard, step 470 involves consecutively inserting the eight-six(86) bytes of payload information into the remaining cells in row six ofthe SONET SPE 300. It should be understood that this step can involveinserting bytes of stuff information to the cells in row six of theSONET SPE 300 when data input port 4 is inactive. It should also beappreciated that this step can involve performing a function toincrement the SONET SPE column counter 124 and the payload informationbyte counter 130 by one (+1) each time a byte of payload information isinserted into a cell. This step can further involve querying the memory116-1 for the eight-six (86) bytes of payload information and receivingthe same from the memory 116-1.

After the eight-six (86) bytes of the fourth eight (8) Mbit/s signal aremapped to the SONET SPE 300, control passes to step 472. In step 472,the method 400 continues to a row seven of the SONET SPE 300. This stepcan involve performing a function to increment the SONET SPE row counter122 by one (+1). In step 474, a byte of path overhead data 322 isinserted into a cell at row seven, column one of a SONET SPE 300. Thisstep can involve performing a function to re-set the SONET SPE columncounter 124 to one (1). After inserting byte 322 into the SONET SPE 300,step 476 is performed. In step 476, a byte a signaling, control, orstuff information 338 is inserted into the SONET SPE 300. This stepinvolves inserting the byte of signaling, control, or stuff information338 into a cell in row seven, column two of the SONET SPE 300. It shouldbe also appreciated that this step can involve performing a function toincrement the SONET SPE column counter 124 and the signaling channelcounter 128 by one (+1). This step can further involve querying thememory 116-1 for the byte of signaling, control, or stuff information338 and receiving the same from the memory 116-1.

Subsequently, the method 400 continues with step 478. In step 478,eighty-five (85) bytes of payload information associated with a fiftheight (8) Mbit/s signal are mapped to the SONET SPE 300 in a byte bybyte manner. It should be appreciated that the cells of the payloadregion 308 are filled in a row by row, from left to right manner. Inthis regard, step 478 involves consecutively inserting the eighty-five(85) bytes of payload information into the remaining cells in row sevenof the SONET SPE 300. It should be appreciated that this step caninvolve inserting bytes of stuff information to the eighty-five (85)cells in row seven of the SONET SPE 300 when data input port 5 isinactive. It should be also appreciated that this step can involveperforming a function to increment the eight (8) Mbit/s signal counter126 by one (+1). This step can involve performing a function toincrement the SONET SPE column counter 124 and the payload informationbyte counter 130 by one (+1) each time a byte of payload information isinserted into a cell. This step can further involve querying the memory116-1 for the eighty-five (85) bytes of payload information andreceiving the same from the memory 116-1.

Thereafter, step 480 is performed where the method 400 continues to arow eight of the SONET SPE 300. This step can involve performing afunction to increment the SONET SPE row counter 122 by one (+1). In step482, a byte of path overhead data 324 is inserted into a cell at roweight, column one of a SONET SPE 300. This step can involve performing afunction to re-set the SONET SPE column counter 124 to one (1).

As shown in FIG. 4C, the method 400 continues with step 484. In step484, forty-three (43) bytes of payload information associated with thefifth eight (8) Mbit/s signal are mapped to the SONET SPE 300 in a byteby byte manner. It should be appreciated that the cells of the payloadregion 308 are filled in a row by row, from left to right manner. Inthis regard, step 484 involves consecutively inserting the forty-three(43) bytes of payload information into forty-three (43) cells in roweight of the SONET SPE 300. It should be appreciated that this step caninvolve inserting bytes of stuff information to the forty-tree (43)cells in row eight of the SONET SPE 300 when the data input port 5 isinactive. It should be further appreciated that this step can involveperforming a function to increment the SONET SPE column counter 124 andthe payload information byte counter 130 by one (+1) each time a byte ofpayload information is inserted into a cell. This step can furtherinvolve querying the memory 116-1 for the forty-three (43) bytes ofpayload information and receiving the same from the memory 116-1.

In step 486, a byte of signaling, control, or stuff information 340 isinserted into the SONET SPE 300. This step involves inserting the byteof signaling, control, or stuff information 340 into a cell in roweight, column forty-five of the SONET SPE 300. It should be appreciatedthat a byte of stuff information is inserted into the cell in row eight,column forty-five of the SONET SPE 300 when the signaling channel port12 is inactive. It should be also appreciated that this step can involveperforming a function to increment the SONET SPE column counter 124 andthe signaling channel counter 128 by one (+1). This step can furtherinvolve querying the memory 116-1 for the byte of signaling, control, orstuff information 340 and receiving the same from the memory 116-1.

After step 486, control passes to step 488 where forty-two (42) bytes ofpayload information associated with a sixth eight (8) Mbit/s signal aremapped to the SONET SPE 300 in a byte by byte manner. It should beappreciated that cells of the SONET SPE 300 are filled in a row by row,from left to right manner. In this regard, step 488 involvesconsecutively inserting the forty-two (42) bytes of payload informationinto the remaining cells in row eight of the SONET SPE 300. It should beappreciated that this step can involve inserting bytes of stuffinformation to the forty-two (42) cells in row eight of the SONET SPE300 when the data input port 6 is inactive. It should also beappreciated that this step can involve performing a function toincrement the eight (8) Mbit/s signal counter 126 by one (+1) and tore-set the payload information byte counter 130 to one (1). This stepcan involve performing functions to increment the SONET SPE columncounter 124 and the payload information byte counter 130 by one (+1)each time a byte of payload information is inserted into a cell. Thisstep can further involve querying the memory 116-1 for the forty-two(42) bytes of payload information and receiving the same from the memory116-1.

Subsequent to mapping the forty-two (42) bytes of a sixth eight (8)Mbit/s signal, control passes to step 490 where the method 400 continuesto a row nine of the SONET SPE 300. This step can involve performing afunction to increment the SONET SPE row counter 122 by one (+1). In step492, a byte of path overhead data 326 is inserted into a cell at rownine, column one of a SONET SPE 300. This step can involve performing afunction to re-set the SONET SPE column counter 124 to one (1).

The method 400 continues with step 494 where eighty-six (86) bytes ofpayload information associated with the sixth eight (8) Mbit/s signalare mapped to the SONET SPE 300 in a byte by byte manner. I should beappreciated that cells of the SONET SPE 300 are filled in a row by row,from left to right manner. In this regard, step 494 involvesconsecutively inserting the eighty-six (86) bytes of payload informationinto eighty-six (86) cells in row nine of the SONET SPE 300. It shouldbe appreciated that this step can involve inserting bytes of stuffinformation to the eighty-six (86) cells in row nine of the SONET SPE300 when the data input port 6 is inactive. It should also beappreciated that his step can involve performing a function to incrementthe SONET SPE column counter 124 and the payload information bytecounter 130 by one (+1) each time a byte of payload information isinserted into a cell. I should further be appreciated that this step caninvolve querying the memory 116-1 for the eighty-six (86) bytes ofpayload information and receiving the same from the memory 116-1. Uponmapping the eighty-six (86) bytes to the SONET SPE 300 , step 496 isperformed where the method 400 ends.

A person skilled in the art will appreciate that the method 400 is oneembodiment of a method for mapping a plurality of eight (8) Mbit/ssignals to the SONET SPE 300. However, the invention is not limited inthis regard and any other method for mapping a plurality of eight (8)Mbit/s signals to a SONET SPE can be used without limitation. Forexample, the method 400 can be absent of steps 408, 414, and 416. Also,the up-counters 132, 134, 136, 138, 140 can alternatively be selected asdown-circuit counters. In these regards, FIGS. 4A-4C can be amendedaccordingly.

Referring now to FIG. 5, there is provided a format diagram of a SONETSPE 500 that is useful for understanding the invention. As shown in FIG.5, the SONET SPE 500 is comprised of a path overhead region 506 and apayload region 508. The path overhead region 506 occupies the firstcolumn of the SONET SPE 500, thus includes nine bytes 510, 512, 514,516, 518, 520, 522, 524, 526 of path overhead data. The payload region508 occupies eight-six (86) columns by nine (9) rows of bytes. As shownin FIG. 5, the payload region 508 is also comprised of six (6) bytes ofsignaling, control, and/or stuff information 530, 532, 534, 536, 538,540. The payload region 508 also includes seven hundred sixty-eight (86columns×9 rows−6 bytes=768) bytes of payload information 550, 552, 554,556, 558, 560 associated with six (6) eight (8) Mbit/s signal. In thisregard, the payload region 508 includes one hundred twenty-eight (768bytes/6 signals=128) bytes of payload information 550, 552, 554, 556,558, 560 per eight (8) Mbit/s signal.

It should be appreciated that a byte of signaling, control, or stuffinformation 530, 532, 534, 536, 538, 540 reside after bytes of payloadinformation 550, 552, 554, 556, 558, 560 associated with an eight (8)Mbit/s signal. For example, byte 530 resides after the bytes of payloadinformation 550 associated with a first eight (8) Mbit/s signal.Similarly, byte 532 resides after the bytes of payload information 552associated with a second eight (8) Mbit/s signal. Likewise, byte 534reside after the bytes of payload information 554 associated with athird eight (8) Mbit/s signal. Byte 536 resides after the bytes ofpayload information 556 associated with a forth eight (8) Mbit/s signal.Byte 538 resides after the bytes of payload information 558 associatedwith a fifth eight (8) Mbit/s signal. Byte 540 resides after the bytesof payload information 560 associated with a sixth eight (8) Mbit/ssignal.

It should also be appreciated that the format of a SONET SPE 500provides for a method to transport a plurality of eight (8) Mbit/ssignals efficiently over the SONET based network 108. For example, ifthe six (6) bytes of signaling, control, and/or stuff information 530,532, 536, 538, 540 are unused, the ‘Total SPE bytes used’ equals sevenhundred sixty-eight (768). The ‘payload capacity’ equals seven hundredseventy-four (774). As such, the ‘transport efficiency’ equalsapproximately ninety-nine point two percent (99.2%). see Equation (1).Alternatively, if the six (6) bytes of signaling, control, and/or stuffinformation 530, 532, 534, 536, 538, 540 are used, the ‘Total SPE bytesused’ equals seven hundred seventy-four (774). The ‘payload capacity’equals seven hundred seventy-four (774). Therefore, the ‘transportefficiency’ equals one hundred percent (100%). see Equation (1).

A person skilled in the art will appreciate that a method similar tothat shown in FIGS. 4A-4C can be used to fill the SONET SPE 500 withbytes of information. Specifically, the bytes of payload information550, 552, 554, 556, 560 can be mapped to the SONET SPE 500 in a byte bybyte manner. The cells of the SONET SPE 500 can be filled from top tobottom in a manner processing row by row, from left to right in eachrow. The counters 122, 124, 126, 128, 130 can be set, re-set, andincremented in a manner similar to that described above (in relation toFIGS. 4A-4C).

A person skilled in the art will also appreciate that the format of aSONET SPE 500 is one embodiment of a SONET SPE format. However, theinvention is not limited in this regard and any other SONET SPE formatcan be used without limitation.

Referring now to FIG. 6, there is provided a format diagram of a SONETSPE 600 that is useful for understanding the invention. As shown in FIG.6, the SONET SPE 600 is comprised of a path overhead region 606 and apayload region 608. The path overhead region 606 occupies the firstcolumn of the SONET SPE 600, thus includes nine bytes 610, 612, 614,616, 618, 620, 622, 624, 626 of path overhead data. The payload region608 occupies eighty-six (86) columns by nine (9) rows of bytes. As shownin FIG. 6, the payload region 608 is comprised of six (6) bytes ofsignaling, control, or stuff information 630, 632, 634, 636, 638, 640.The payload region 608 is also comprised of seven hundred-eight (86columns×9 rows−6 bytes=768) bytes of payload information 650, 652, 654,656, 658, 660 associated with six (6) eight (8) Mbit/s signal. In thisregard, the payload region 608 includes one hundred twenty-eight (768bytes/6 signals=128) bytes of payload information 650, 652, 654, 656,658, 660 per eight (8) Mbit/s signal. It should be appreciated that thesix (6) bytes of signaling, control, or stuff information 630, 632, 638,640 reside prior to the bytes of payload information 650, 652, 654, 656,660 associated with the six (6) eight (8) Mbit/s signals.

It should also be appreciated that the format of a SONET SPE 600provides for a method to transport a plurality of eight (8) Mbit/ssignals efficiently over the SONET based network 108. For example, ifthe six (6) bytes of signaling, control, and/or stuff information 630,632, 634, 636, 638, 640 are unused , the ‘Total SPE bytes used’ equalsseven hundred sixty-eight (768). The ‘payload capacity’ equals sevenhundred seventy-four (774). As such, the ‘transport efficiency’ equalsninety-nine point two percent (99.2%). see Equation (1). Alternatively,if the six (6) bytes of signaling, control, and/or stuff information630, 632, 636, 638, 640 are sued, the ‘Total SPE bytes used’ equalsseven hundred seventy-four (774). The ‘payload capacity’ equals sevenhundred seventy-four (774). Therefore, ‘transport efficiency’ equals onehundred percent (100%). see Equation (1).

A person skilled in the art will appreciate that a method similar tothat shown in FIGS. 4A-4C can be used to fill the SONET SPE 600 withbytes of information. Specifically, the bytes of payload information650, 652, 654, 656, 658, 660 can be mapped to the SONET SPE 600 in abyte by byte manner. The cells of the SONET SPE 600 can be filled fromtop to bottom in a manner proceeding row by row, from left to right ineach row. The counters 122, 124, 126, 128, 130 can be set, re-set, andincremented in a manner similar to that described above (in relation toFIGS. 4A-4C).

A person skilled in the art will appreciate that the format of a SONETSPE 600 is one embodiment of a SONET SPE format. However, the inventionis not limited in this regard and any other SONET SPE format can be usedwithout limitation.

Referring now to FIG. 7, there is provided a format diagram of a SONETSPE 700 that is useful for understanding the invention. As shown in FIG.7, the SONET SPE 700 is comprised of a path overhead region 706 and apayload region 708. The path overhead region 706 occupies the firstcolumn of the SONET SPE 700, thus includes nine bytes 710, 712, 714,716, 720, 722, 724, 726 of path overhead data. The payload region 708occupies eighty-six (86) columns by nine (9) rows of bytes. As shown inFIG. 7, the payload region 708 is comprised of seven hundred sixty-eight(86 columns×9 rows−6 bytes=768) bytes of payload information 750, 752,754, 756, 758, 760 associated with six (6) eight (8) Mbit/s signal. Inthis regard, the payload region 708 includes one hundred twenty-eight(768 bytes/6 signals=128) bytes of payload information 750, 752, 754,756, 758, 760 per eight (8) Mbit/s signal. The payload region 708 isalso comprised of six (6) bytes of signaling, control, or stuffinformation 730, 732, 734, 736, 738, 740. It should be appreciated thatthe six (6) bytes of signaling, control, or stuff information 730, 752,754, 756, 758, 760 associated with the six (6) eight (8) Mbit/s signals.

It should also be appreciated that the format of a SONET SPE 700provides for a method to transport a plurality of eight (8) Mbit/ssignals efficiently over the SONET based network 108. For example, ifthe six (6) bytes of signaling, control, and/or stuff information 730,732, 734, 736 738, 740 are unused, the ‘Total SPE bytes used’ equalsseven hundred sixty-eight (768). The ‘payload capacity’ equals sevenhundred seventy-four (774). As such, the ‘transport efficiency’ equalsninety-nine point two percent (99.2%). see Equation (1). Alternatively,if the six (6) bytes of signaling, control, and/or stuff information730, 732, 734, 736, 738, 740 are used, the ‘Total SPE bytes used ’equals seven hundred seventy-four (774). The ‘payload capacity’ equalsseven hundred seventy-four (774). Therefore, the ‘transport efficiency’equals one hundred percent (100%). see Equation (1).

A person skilled in the art will appreciate that a method similar tothat shown in FIGS. 4A-4C can be used to fill the SONET SPE 700 withbytes of information. Specifically, the bytes of payload information750, 752, 754, 756, 758, 760 can be mapped to the SONET SPE 700 in abyte by byte manner. The cells of the SONET SPE 700 can be filled fromtop to bottom is a manner proceeding row by row, from left to right ineach row. The counters 122, 124, 126, 128, 130 can be set, re-set, andincremented in a manner similar to that described above (in relation toFIGS. 4A-4C).

A person skilled in the art will appreciate that the format of a SONETSPE 700 is one embodiment of a SONET SPE format. However, the inventionis not limited in this regard and any other SONET SPE format can be usedwithout limitation.

All of the apparatus, methods and algorithms disclosed and claimedherein can be made and executed without undue experimentation in lightof the present disclosure. While the invention has been described interms of preferred embodiments, if will be apparent to those of skill inthe art that variations may be applied to the apparatus, methods andsequence of steps of the method without departing from the concept,spirit and scope of the invention. More specifically, it will beapparent that certain components may be added to, combined with, orsubstituted for the components described herein while the same orsimilar results would be achieved. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined.

1. A system for transporting a plurality of payload signals efficientlyover a SONET based network, comprising: a plurality of data input portsconfigured to receive said plurality of payload signals transmitted at afirst data transfer rate, said plurality of payload signals comprisingpayload information; a plurality of signaling input ports configured toreceive a plurality of signaling signals transmitted at a second datatransfer rate different from the first data transfer rate, saidplurality of signaling signals including signaling information; and atleast one data processing circuit configured to map said plurality ofpayload signals and said plurality of signaling signals directly into aSONET SPE of a SONET STS-1 frame exclusive of virtual tributaries, saidmapping achieved by transferring a plurality of bytes of said payloadinformation in sequence from each of said plurality of payload signals,breaking said payload information into a plurality of byte segments,each byte segment comprising a predetermined number of bytes of saidpayload information, mapping said plurality of byte segments to saidSONET SPE in a byte by byte manner into a plurality of cells of saidSONET SPE proceeding row by row, in a left to right manner, andproceeding from top to bottom of said SONET SPE, inserting at least onestuff byte segment into said SONET SPE if any one of said plurality ofdata input ports is determined to be inactive, said stuff byte segmentcomprising said predetermined number of bytes; inserting a plurality ofbytes of path overhead data into a plurality of cells in rows onethrough nine, column one of said SONET SPE or at a SONET SPE startinglocation defined by at least one SONET transport overhead pointer byte,and inserting bytes of non-payload information into cells in at leastone column of the SONET SPE other than said column one containing saidplurality of bytes of path overhead data; wherein said non-payloadinformation is selected from the group comprising said signalinginformation, stuff information and control information, and said firstand second data transfer rates are less than a third data transfer rateof said SONET STS-1 frame.
 2. The system according to claim 1, whereinsaid at least one data processing circuit is further configured toinsert in said SONET SPE immediately preceding each respective one ofsaid plurality of byte segments a byte of said non-payload information.3. The system according to claim 1, wherein said at least one dataprocessing circuit is further configured to insert a plurality of bytesof said non-payload information after a first byte of said plurality ofbytes of path overhead data.
 4. The system according to claim 3, whereinsaid at least one data processing circuit is further configured toinsert said plurality of bytes of said non-payload information into aplurality of cells in a row one, columns two through seven of said SONETSPE.
 5. The system according to claim 1, wherein said at least one dataprocessing circuit is further configured to insert in said SONET SPEimmediately following each respective one of said plurality of bytesegments a byte of said non-payload information.
 6. The system accordingto claim 1, wherein said at least one data processing circuit is furtherconfigured to insert said plurality of bytes of said non-payloadinformation into a last six cells of said SONET SPE.
 7. The systemaccording to claim 6, wherein said at least one data processing circuitis further configured to insert said plurality of bytes of saidnon-payload information into a plurality of cells in a row nine, columnseighty-two through eighty-seven of said SONET SPE.
 8. The systemaccording to claim 1, wherein said at least one data processing circuitis further configured to determine whether each of said plurality ofsaid data input ports is active or inactive.
 9. The system according toclaim 8, wherein said at least one data processing circuit is furtherconfigured to insert at least one stuff byte into said SONET SPE if adata input port of any of one of said plurality of data input ports isinactive.
 10. The system according to claim 1, wherein each of saidplurality of byte segments is comprised of one hundred twenty eightbytes of payload information.
 11. The system according to claim 1,wherein said at least one data processing circuit is further configuredto determine whether each signaling input port of said plurality ofsignaling input ports is active or inactive.
 12. The system according toclaim 11, wherein said at least one data processing circuit is furtherconfigured to transfer a plurality of bytes of said signalinginformation in sequence from each one of said plurality of signalingsignals to obtain a signaling byte segment.
 13. The system according toclaim 12, wherein said at least one data processing circuit isconfigured to insert said signaling byte segment into said SONET SPE ifa signaling input port of a corresponding one of said plurality ofsignaling input ports is active.
 14. The system according to claim 11,wherein said at least one data processing circuit is further configuredto insert a byte of stuff information into said SONET SPE if a signalinginput port of a corresponding one of said plurality of signaling inputports is inactive.
 15. A method for transporting a plurality of payloadsignals efficiently over a SONET based network, comprising: receiving ata plurality of data input ports said plurality of payload signalstransmitted at a first data transfer rate, said plurality of payloadsignals comprising payload information; receiving at a plurality ofsignaling input ports a plurality of signaling signals transmitted at asecond data transfer rate different from the first data transfer rate,said plurality of signaling signals including signaling information; andmapping said plurality of payload signals and said plurality ofsignaling signals directly into a SONET SPE of a SONET STS-1 frameexclusive of virtual tributaries, said mapping including: transferring aplurality of bytes of said payload information in sequence from each ofsaid plurality of payload signals and breaking said payload informationinto a plurality of byte segments, each byte segment comprising apredetermined number of bytes of said payload information; mapping saidplurality of byte segments directly into a SONET SPE of a SONET STS-1frame in a byte by byte manner into a plurality of cells of said SONETSPE proceeding row by row, in a left to right manner, and proceedingfrom top to bottom of said SONET SPE; inserting a plurality of bytes ofpath overhead data into a plurality of cells in rows one through nine,column one of said SONET SPE or at a SONET SPE starting location definedby at least one SONET transport overhead pointer byte; and insertingbytes of non-payload information into cells in at least one column ofthe SONET SPE other than said column one containing said plurality ofbytes of path overhead data; wherein said non-payload information isselected from the group comprising said signaling information, stuffinformation and control information, and said first and second datatransfer rates are less than a third data transfer rate of said SONETSTS-1 frame.
 16. The method according to claim 15, further comprisinginserting in said SONET SPE immediately preceding each respective one ofsaid plurality of byte segments a byte of said non-payload information.17. The method according to claim 15, further comprising inserting aplurality of bytes of said non-payload information after a first byte ofsaid plurality of bytes of path overhead data.
 18. The method accordingto claim 17, further comprising inserting said plurality of bytes ofsaid non-payload information into a plurality of cells in a row one,columns two through seven of said SONET SPE.
 19. The method according toclaim 15, further comprising inserting in said SONET SPE immediatelyfollowing each respective one of said plurality of byte segments a byteof said non-payload information.
 20. The method according to claim 15,further comprising inserting said plurality of bytes of said non-payloadinformation into a last six cells of said SONET SPE.
 21. The methodaccording to claim 20, further comprising inserting said plurality ofbytes of said non-payload information into a plurality of cells in a rownine, columns eighty-two through eighty-seven of said SONET SPE.
 22. Themethod according to claim 15, further comprising determining whethereach data input port of a plurality of data input ports is active orinactive.
 23. The method according to claim 22, further comprisinginserting at least one stuff byte into said SONET SPE if a data inputport of any one of said plurality of data input ports is inactive. 24.The method according to claim 15, further comprising selecting each ofsaid plurality of byte segments to include one hundred twenty eightbytes of payload information.
 25. The method according to claim 15,wherein each of said plurality of signaling signals respectivelycorresponds to one of said plurality of payload signals.
 26. The methodaccording to claim 25, further comprising determining whether eachsignaling input port of a plurality of signaling input ports is activeor inactive.
 27. The method according to claim 26, further comprisingtransferring a plurality of bytes of said signaling information fromeach of said plurality of signaling signals to obtain a signaling bytesegment.
 28. The method according to claim 27, further comprisinginserting said signaling byte segment into said SONET SPE if a signalinginput port of said plurality of signaling input ports is active.
 29. Themethod according to claim 26, further comprising inserting a byte ofstuff information into said SONET SPE if a signaling input port of saidplurality of signaling input ports is inactive.
 30. A method fortransporting a plurality of 8 Mbit/s payload signals efficiently over aSONET based network, comprising: receiving, at each of six data inputports, one of six 8 Mbit/s payload signals transmitted at a first datatransfer rate of eight megabits per second, each of said 8 Mbit/spayload signals comprising payload information; receiving, at each of aplurality of signaling input ports, one of a plurality of signalingsignals transmitted at a second data transfer rate different from thefirst data transfer rate, each signaling signal of said plurality ofsignaling signals including signaling information; mapping saidplurality of payload signals and said plurality of signaling signalsdirectly into a SONET SPE of a SONET STS-1 frame exclusive of virtualtributaries, said mapping including: transferring a plurality of bytesof said payload information in sequence from each of said 8 Mbit/spayload signals and breaking said payload information into a pluralityof byte segments, each byte segment comprising 128 bytes of said payloadinformation; mapping said plurality of byte segments directly into aSONET SPE of a SONET STS-1 frame in a byte by byte manner into aplurality of cells of said SONET SPE proceeding row by row, in a left toright manner, and proceeding from top to bottom of said SONET SPE;inserting a plurality of bytes of path overhead data into a plurality ofcells in rows one through nine, column one of said SONET SPE or at aSONET SPE starting location defined by at least one SONET transportoverhead pointer byte; and inserting six bytes of non-payloadinformation into cells in at least one column of said SONET SPE otherthan said column one containing said plurality of bytes of path overheaddata; wherein said non-payload information is selected from the groupcomprising said signaling information, stuff information and controlinformation, and said first and second data transfer rates are less thana third data transfer rate of said SONET STS-1 frame.